Conventionally, invariant current charging systems are currently recommended and supplied by equipment manufactures.
Invariant current charging systems invoke premature capacity loss of lead-acid batteries when combined with high rates of discharge and recharge. There are several factors that contribute to battery failures. They have a compounding affect. The decline in capacity is associated with a progressive change in the nature of the plates active material. The active material which starts out porous with low crystallinity changes to a less porous and a more defined crystallinity in the cycled mass. Conventional charging also invokes the growth of small crystals that completely blanket the surface of the plates. This resistive layer of lead oxide PBO is most responsible for the increased internal impedance of batteries.
Further decline in battery capacity due to reduced available re-active surface area and reduced battery acid strength result in lowered battery voltage output, result in softening and shedding of active material. Continued conventional charging results in excessive gassing, increased crystallization, increased operating temperature, resulting in physical damage to the battery caused by distortion due to crystal growth and resulting in heat damage due to internal impedance.
Inventors have previously proposed various types of pulsed voltage charging devices.